Photographic Glossary-P

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PAL
Phase Alternation Line. System for minimising hue errors in colour transmission used in the EU.

Pan (Panchromatic)
Designation of films that record all colors in tones of about the same relative brightness as the human eye sees in the original scene, sensitive to all visible wave-lengths.

Pan Format
"Pan" format - one of the three selectable Advanced Photo System print formats; a 1:3 aspect ratio that produces prints of 3.5 x 10.5 inches or up to 4.5 x 11.5 inches; suitable for panoramic shots and tall or wide subjects.

Pan Head
Without the aid of a Ball Head or pan head, a camera mounted on a tripod or monopod can only be used in horizontal format. The addition of a pan head allows the camera to be rotated around 3 separate axes independent of each other allowing fine control of camera placement.

Panchromatic Films
Films which must be handled to total darkness until completely processed. Example: Kodak T-Max, Tri-x, Plus-X, Ilford Delta, Agfa APX.

Panchromatic( Pan )
Is a photographic emulsion sensitive to all the colours of the visible spectrum and to a certain amount of ultra-violet light. The sensitivity is not uniform throughout the spectrum.

Panning
Moving the camera so that the image of a moving object remains in the same relative position in the viewfinder as you take a picture. The eventual effect creates a strong sense of movement.

Panorama
A broad view, usually scenic or a series of images stitched together to create a picture wider than what the camera is normally capable of capturing.

Panoramic camera
Camera with a special type of scanning lens which rotates. Or a static lens camera with a wide format e.g. 6cm x 17cm.

Paper base
Is the support for the emulsion used in printing papers.

Paper grade
Is a numerical terminological description of paper contrast: numbers 0-1 soft; numbers 2 normal; number 3 hard; number 4-5 very hard; number 6 ultra hard. Similar grade number from different manufactures do not have the same characteristics.

Paper safe
Is a light-tight container for unexposed photographic papers, with an easy open positive closing lid.

Parallax Distortion
Twin Lens Reflex camera use two lenses, one for taking the photograph, the other for focusing and viewing. At very close distances, the images viewed through the viewing lens will be different than what the film sees through the taking lens. Beyond a few feet, the angles caused by the separation of the lenses is minimal and will not be seen.

Parallax error
Occurs when shooting very close up with a viewfinder camera. The photographer does not see an accurate indication of the subjects position relative to the lens, so parts of the subject that he or she thinks will be photographed are missing on the final photograph. Parallax error is overcome in more expensive compact and viewfinder cameras which adjust the viewfinder to compensate for the distance the subject is away from the camera.

Parallax focus
Focusing system in some compact cameras that compensates for the difference between viewfinder and lens placement.

Parallax
The difference in point of view that occurs when the lens (or other device) through which the eye views a scene is separate from the lens that exposes the film. With a lens-shutter camera, parallax is the difference between what the viewfinder sees and what the camera records, especially at close distances. This is caused by the separation between the viewfinder and the picture-taking lens. There is no parallax with single-lens-reflex cameras because when you look through the viewfinder, you are viewing the subject through the picture-taking lens.

Parallel cable
The cable connection between the computer and another device's parallel ports ( usually a printer ), which allows a computer to send several bits of data simultaneously.

Parallel port
A connector on your computer that allows you to connect to other devices, such as a printer . Another name for parallel port is LPT port.

Parallel Processing
When an array of processors or segments of the CPU work at the same time to speed processing or multi-task.

Path
A path is an overlay that sits on top of your image, allowing you to work with it.

PC (photographic)
Prontor/Compur. The clip on socket of the flash mode terminal. 2) Perspective control. Also known as tilt or shift lenses. Lenses that allow for correction of linear distortion resulting from high or low camera angle. Most are with gear or sliding mechanism and most require manual metering.

PC Cord
Before the days of hotshoe flash connectors and TTL flashes, the method of connecting the flash to the camera body was by PC cord. This cord if fairly thin and can be easily broken but can fire a flash from a great distance if necessary. The purpose of sync cords is to allow the camera to control the flash, so the flash fires at the correct time. Other common names for electrical cords to connect flash to camera are PC cord, sync cord and synch cord. One type of electrical connector on camera bodies is called a PC socket, whence the name, PC cord. Sync and synch are both intended to be abbreviations of the word synchronization.

PC Terminal /PC socket
Some older flash units may not have a hot shoe on the flash unit and would need cable connection to fire timely. It is a threaded collar surrounding the center electrical part of the socket. Some flash cords have a connector that makes electrical contact with the center part of the socket and is held securely in place by a threaded ring which screws into the outer part of the socket on the camera body. It is another alternative way to sync the electronic flash on the camera. Some of the modern autofocus cameras have omitted this feature on the body. It can also be used to activate another flash unit via sync cord in a multiple flash setup. PC sockets and common PC cords fit together by pushing the connector on the cord into the socket on the camera. It remains connected only because of friction.

PC
Personal Computer.

PCMCIA card
( Personal Computer Memory Card International Association ) card. used in digital cameras to transfer photos to a notebook or PC.

PDF
(PortableDocumentFormat) is a file format that has captured all the elements of a printed document as an electronic image that you can view, navigate, print, or forward to someone else. PDF files are created using Adobe Acrobat (NOT the free reader), Acrobat Capture, or similar products. To view and use the files, you need the free Acrobat Reader, which you can easily download. Once you've downloaded the Reader, it will start automatically whenever you want to look at a PDF file.
PDF files are especially useful for documents such as magazine articles, product brochures, or flyers in which you want to preserve the original graphic appearance online. A PDF file contains one or more page images, each of which you can zoom in on or out from. You can page forward and backward.

Perforations
Regularly and accurately spaced holes punched throughout the length of film for still cameras. Basically the perforation function as a guide for precision registration of film and also provide mechanical movement from frame to frame.

Peripheral
A term used to collectively describe computer accessories such as printers, modems, scanners, etc.

Perspective
The angle or level from which the photographer takes the photograph; the camera and photographer's "point of view". The rendition of apparent space in a flat photograph, i.e., how far the foreground and background appear to be separated from each other; determined by only one factor: the camera-to-subject distance; if objects appear in their normal size relations, the perspective is considered "normal"; if the foreground objects are much larger than the ones in the background, the perspective is considered "exaggerated"; when there is little difference in size between foreground and background, we say the perspective looks "compressed."

ph
A measure of acidity or alkalinity. pH7 is neutral; lower numbers indicate increasing acidity, while higher numbers indicate increasing alkalinity. pH control is an essential aspect of photographic chemistry, and one which is often neglected.

Phosphor
The chemical substance on the inside face of a computer screen that illuminates when electrically charged. The colour accuracy and luminance values of phosphors change over time, necessitating regular monitor calibration if consistent colour is required.

Photo CD
A popular storage method for digital images. In the basic Kodak Photo CD configuration, five different levels of image quality are stored for each in an Image Pac.

Photo diode
A semi conductor measuring or converting light into electrical current, commonly used in scanners and CCD's

Photo File Index Print
A basic system feature that makes ordering reprints and enlargements easy; the small print shows a positive, "thumbnail"-sized version of every picture on an Advanced Photo System film roll; accompanies all prints and negatives returned in the sealed film cassette by the photofinisher; each thumbnail picture is numbered on the index print to match negative frames inside the cassette.

Photofinisher Service Certification
Program developed by the System Developing Companies to give special recognition to photofinishers and retailers who provide the minimum Advanced Photo System feature set; an identifying logo signals to consumers which photofinishers and retailers provide all of the mandatory benefits of the system.

Photogravure
An intaglio printing process in which the image has been placed on the plate by photographic means using carbon tissues.

Photolamp (3400K)
Photographic lamp giving more light than a normal lamp of the same wattage, at the expense of filament life. Often referred to by the trade mark Photo Hood. Are used with type A colour films.

Photomicrography
The process of taking photographs of minute objects using a camera and a microscope; not to be confused with "microphotography," the process of making minute photographs of large objects.

Photomontage
A photographic composition assembled from pieces of different photographs or of different negatives, closely arranged or superimposed upon each other. Sometimes graphic material is added to the combination.

Photoshop
A sophisticated software program, produced by Adobe Systems, for editing and processing of images.

Photosite
A single photosensitive element in a CCD which translates to one pixel in the resultant image. Also known as a CCD Element

PICT
Macintosh picture. A storage format for digital images designed for the Macintosh.

Picture angle
The angle of coverage of a lens usually measured across the diagonal of the picture frame; varies with focal length: the longer the focal length, the narrower the picture angle; the shorter the focal length, the wider the picture angle. Telephoto ratio Is derived by dividing the distance from the front vertex of a lens to the front vertex by the focal length. The smaller the telephoto ratio, the smaller the total length of the lens.

Pigment
Particles that absorbs and reflect light and appear coloured to our eyes. The substance that gives ink its colour.

Pincushion distortion
A lens aberration or defect that causes straight lines to bow inward toward the center of the image. The opposite of barrel distortion; straight lines are bowed in toward the middle to resemble the sides of a pincushion; present in small amounts in some telephoto and telephoto-zoom lenses.

Pinhole Photography involves making a pinhole in the end of a box, tube, or any other object that can be made light proof and then placing film or paper in the other end to expose by the light entering. Caps are also available for cameras as well that have very precise holes cut in them at proper focal distances. Pinhole camera's have an enormous depth of field due to the very small aperture, enough that some consider photographs to be 3 dimensional because nearly everything in the photograph is in focus. For thousands of years the understanding that if light is projected through a small hole, any image between the light source and the hole will be projected through the hole onto a surface on the other side. This effect can be seen when walking through the forest on a sunny day and looking at the ground where images are being projected from holes in the leaves.

Pinhole
1. A small clear spot on a negative usually caused by dust on the film during exposure or development or by a small air bubble that keeps developer from the film during development. 2. The tiny opening in a pinhole camera that produces an image. An old, but currently popular way of taking pictures using a simple box without a lens, but with a tiny hole and a sheet of film pinned inside opposite the hole. Produces unique perspective and dreamy focus.

Pixel dropping
A subsampling technique used to reduce the number of pixels in an image by dropping every nth pixel from the scan.

Pixel Modulation
A process used in printing which changes the brightness of individual pixels by changing the pixel size.

Pixel skipping
A means of reducing image resolution by simply deleting pixels throughout the image.

Pixel
Short for Picture Element, a pixel is a single point in a graphic image. Graphics monitors display pictures by dividing the display screen into thousands (or millions) of pixels, arranged in rows and columns. The pixels are so close together that they appear connected.
The number of bits used to represent each pixel determines how many colours or shades of gray can be displayed. For example, in 8-bit colour mode, the colour monitor uses 8 bits for each pixel, making it possible to display 2 to the 8th power (256) different colours or shades of gray.
On colour monitors, each pixel is actually composed of three dots - a red, a blue, and a green one. Ideally, the three dots should all converge at the same point, but all monitors have some convergence error that can make colour pixels appear fuzzy
Also used in measuring image size and resolution, i.e., 640 X 480 is the pixel resolution of most VGA Monitors. (Note pixels are square in computers and most digital cameras, they are rectangular in video cameras and television). The bit depth and surface size of the individual pixels on an image sensor controls its sensitivity to light. (Equivalent ISO).

Pixelization
The stair-stepped appearance of a curved or angled line in digital imaging. The smaller the pixels, and the greater their number, the less apparent the "pixelization" of the image. Also known as the "jaggies".

Plane of focus
The point in a camera where all the light rays converge, forming a sharp image. In a camera, this corresponds to the film plane.

Plane
Level surface. Used in photography chiefly in respect to focal plane, an imaginary level surface perpendicular to the lens axis in which the lens is intended to form an image. When the camera is loaded the focal plane is occupied by the film surface.

Plasma display
A display screen that has gas contained between two panels. When specific x-axis ( horizontal ) and y-axis ( vertical ) dots on the panels are electrically charged, the gas in that area glows.

Platen
The glass scanning region on a flatbed scanner.

Platform
The brand or computer type you are using, i.e., a Windows platform or MAC platform.

Platinum/palladium
A print in which the final image is formed in platinum or palladium. Both of these processes are extremely permanent and have delicate rich tones and ranges of greys that are unattainable in silver prints. These processes are enjoying a revival today with a number of contemporary photographers coating their own paper.

Plug and play
The ability to install equipment with little or no setup.

Plug-in
The plug-in architecture was first popularized by Adobe Photoshop and is now the de facto standard for all major imaging programs. Unlike TWAIN it allows more flexibility in design so acquire, export, and specific task can be performed within a software application. This is the preferred choice of operation in the Macintosh and 'Power User' computers. Plug-In ideology has spread to other applications like Netscape Navigator, Macromedia Director, and so on. Not all plug-ins work with all products, specific interfaces are required for different types of software. Plug-Ins are also software version dependent.

PMT
Photo Multiplier Tube. The light sensing devices generally used in drum scanners.

PNG
Developed as a patent-free alternative to GIF, the Portable Network Graphics (PNG) format is used for losslessly compressing and displaying images on the World Wide Web. Unlike GIF, PNG supports 24-bit images and produces background transparency without jagged edges; however, some older versions of Web browsers may not support PNG images. The PNG format supports grayscale and RGB colour modes with a single alpha channel, and Bitmap and indexed-colour modes without alpha channels. PNG uses the saved alpha channel to define transparency in the file.

Point and Shoot Camera
A camera with no interchangeable lenses. The lens is permanently fixed to the camera body. P&S cameras come with either zoom lenses, usually ranging from wide angles of ~30mm to zoom ranges of upwards of ~200mm in the more expensive ranges. Typical P&S camera are 38mm-70mm or 38mm-120mm. These cameras are usually very simple to use and require little photographic knowledge.

Point and shoot
A term used for a simple, easy to use camera with a minimum of user controls. Generally the user turns the camera on , aims it at the subject and presses the shutter button. The camera does everything automatically.

Polarising Screen (Filter)
A filter that transmits light travelling in one plane while absorbing light travelling in other planes. When placed on a camera lens or on light sources, it can eliminate undesirable reflections from a subject such as water, glass, or other objects with shiny surfaces. This filter also darkens blue sky.

Polarization
The use of specific filters to control the direction light travels. Effects are the reduction of glare and reflections and the saturation of colours, especially in landscapes.

Polarized light
Light waves vibrating in one plane only as opposed to the multi-directional vibrations of normal rays. Natural effect produced by some reflecting surfaces, such as glass, water, polished wood, etc., but can also be simulated by placing a special screen in front of the light source. The transmission of polarized light is restrained by using a screen at an angle to the plane of polarization.

Polarizing filter
Usually indicates a linear polarizing filter. A linear polarizing filter eliminates various degrees of reflected light from glass, water, plastic, paper and similar surfaces. It can also eliminate light reflections from vapours or floating dust to emphasize a blue sky. Polarizing filters transmit light waves that vibrate in a single direction only; the effect can be seen in the viewfinder as the filter is rotated. (Used to make clouds look full and puffy and skies dark blue)

Polaroid back
A camera back that uses instant film for proofing a scene (checking lighting, composition & basic exposure ) before shooting with traditional film.

Polaroid Transfer
It is possible to float off the emulsion layer of a conventional Polaroid print and apply it to a new paper support with interesting effects.

Ports
Plugs or connectors into which cables are attached.

Positive
The opposite of a negative for example an image with the same tonal relationships as those in the original scan. Most prints and slides are positive.

Positive
The opposite of a negative, an image with the same tonal relationships as those in the original scenes-for example, a finished print or a slide.

Posterization
A photographic or digital graphic effect arising from reducing the number of continuous tones in an image. Can be a deliberate effect or a result of over-manipulation or compression in a digital image.

Posterize
To achieve the impression of continuous tone we need to reproduce 256 differentiation's of tone from white to black. If we break down the tonal range into fewer differentiation's you begin to see the breaks between the individual tones. We call this pasteurization, it often appears in smooth colour gradients.

PPI
Pixel Per Inch. The frequency of the number of samples used to display an image on a computer monitor.

Prescan
A quick, low resolution preview scan of an image to be scan.

Preset iris
Diaphragm with two setting rings or one ring that can be moved to two positions. One is click-stopped, but does not affect the iris, the other moves freely and alters the aperture. The required aperture is preset on the first ring, and the iris closed down with the second just before exposure.

Presoak
To soak film briefly in water prior to immersing it in developer.

Primary colours
The set of colours that can be mixed to produce all the colours in a colour space; in additive systems they are red, green, and blue, while in subtractive systems they are cyan, magenta, and yellow.

Print Film: Film which records the image in a negative format. The negative is then used to render a print, which displays the positive image. Print film has a very wide latitude because during the printing process the color can be adjusted as necessary to produce a pleasing print. Print films often have a latitude of +/- 2 or 3 stops. Print films are also available in Daylight Balanced and Tungsten Balanced

Print
A positive picture, usually on paper, and usually produced from a negative.

Printer resolution
The amount of detail a printer or imagesetter will reproduce, measured in dots per inch (dpi).

Printing Frame
A device used for contact printing that holds a negative against the photographic paper. The paper is exposed by light from an external light source.

Printing-in
(See Burning-in)

Prism
Triangular-shaped glass or other transparent material. When light is passed through a prism, its wavelengths refracts into a rainbow of colours. This demonstrates that light is composed of colour, and indicates the arrangement of colours in the visible spectrum.

Process colours
The four colours (cyan, magenta, yellow, and black) that are combined to print a wide range of colours. When blended, they can reproduce only some of the colours found in nature.

Process control
The stability of a manufacturing process that assures the products produced sable and consistent.

Processing
Developing, fixing, and washing exposed photographic film or paper to produce either a negative image or a positive image.

Profile
An ICC description of a particular imaging input or output device that allows the Colour Management Software to apply the proper transformations to the image file to match the specific limitation of the device.

Program Exposure
An exposure mode on an automatic or autofocus camera that automatically sets both the aperture and the shutter speed for proper exposure.

Program mode
An automatic exposure mode in which the camera adjusts all aspects of exposure.

Programmed Auto
Camera sets both shutter speed and aperture for correct exposure.

Progressive CCD
CCD specially designed for digital cameras, the shape of progressive CCD pixels being square thereby making them ideal for photography.

Progressive Scan
A non-interlaced refresh system for monitors that cuts down on CRT flicker.

Proof
A test print made for the purpose of evaluating density, contrast, colour balance, subject composition, and the like.

Proprietary
The design of programs, systems or equipment that are owned by an entity. This technology may be licensed for use in other applications or systems.

Proxy Image
A low resolution image used in any software programs to show the effects of changes without performing transformations on high resolution files.

Proxy
A representative version or sample of a larger image.

PSD
The native file format of the Adobe Photoshop graphical editing application. Adobe Photoshop is a standard editing application in the print and internet media worlds.

Pull processing
Decreasing the effective speed of film, often to compensate for a mistake in setting ISO. It is usually done by decreasing the development time or the temperature of the developer.

Push processing
Extending development time, usually to compensate for underexposure caused by a film being upgraded to permit a faster shutter than the light allows.

Push
To expose film at a higher film speed rating than the normal, then to compensate in part for the resulting underexposure by giving greater development than normal. This permits shooting at a dimmer light level, a faster shutter, or a smaller aperture that would otherwise be possible.